Some of the nation’s biggest banks and mortgage companies have defrauded veterans and taxpayers out of hundreds of millions of dollars by disguising illegal fees in veterans’ home refinancing loans, according to a whistleblower suit unsealed in federal court in Atlanta.

The suit accuses the companies, including Wells Fargo, Bank of America, J.P. Morgan Chase and GMAC Mortgage, of engaging in “a brazen scheme to defraud both our nation’s veterans and the United States treasury” of millions of dollars in connection with home loans guaranteed by the Department of Veterans Affairs.

“This is a massive fraud on the American taxpayers and American veterans,” James E. Butler Jr., one of the lawyers bringing the suit, said Tuesday.